134 lines
3.9 KiB
C++
134 lines
3.9 KiB
C++
//////////////////////////////////////////////////////////////////////////////
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//
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// (C) Copyright Ion Gaztanaga 2006-2012. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/interprocess for documentation.
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//
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//////////////////////////////////////////////////////////////////////////////
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#include <boost/interprocess/detail/config_begin.hpp>
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#include <boost/interprocess/detail/workaround.hpp>
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//[doc_intrusive
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#include <boost/interprocess/managed_shared_memory.hpp>
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#include <boost/interprocess/smart_ptr/intrusive_ptr.hpp>
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//<-
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#include "../test/get_process_id_name.hpp"
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//->
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using namespace boost::interprocess;
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namespace N {
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//A class that has an internal reference count
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class reference_counted_class
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{
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private:
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//Non-copyable
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reference_counted_class(const reference_counted_class &);
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//Non-assignable
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reference_counted_class & operator=(const reference_counted_class &);
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//A typedef to save typing
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typedef managed_shared_memory::segment_manager segment_manager;
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//This is the reference count
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unsigned int m_use_count;
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//The segment manager allows deletion from shared memory segment
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offset_ptr<segment_manager> mp_segment_manager;
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public:
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//Constructor
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reference_counted_class(segment_manager *s_mngr)
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: m_use_count(0), mp_segment_manager(s_mngr){}
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//Destructor
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~reference_counted_class(){}
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public:
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//Returns the reference count
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unsigned int use_count() const
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{ return m_use_count; }
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//Adds a reference
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inline friend void intrusive_ptr_add_ref(reference_counted_class * p)
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{ ++p->m_use_count; }
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//Releases a reference
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inline friend void intrusive_ptr_release(reference_counted_class * p)
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{ if(--p->m_use_count == 0) p->mp_segment_manager->destroy_ptr(p); }
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};
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} //namespace N {
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//A class that has an intrusive pointer to reference_counted_class
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class intrusive_ptr_owner
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{
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typedef intrusive_ptr<N::reference_counted_class,
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offset_ptr<void> > intrusive_ptr_t;
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intrusive_ptr_t m_intrusive_ptr;
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public:
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//Takes a pointer to the reference counted class
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intrusive_ptr_owner(N::reference_counted_class *ptr)
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: m_intrusive_ptr(ptr){}
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};
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int main()
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{
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//Remove shared memory on construction and destruction
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struct shm_remove
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{
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//<-
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#if 1
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shm_remove() { shared_memory_object::remove(test::get_process_id_name()); }
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~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); }
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#else
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//->
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shm_remove() { shared_memory_object::remove("MySharedMemory"); }
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~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
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//<-
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#endif
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//->
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} remover;
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//<-
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(void)remover;
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//->
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//Create shared memory
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//<-
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#if 1
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managed_shared_memory shmem(create_only, test::get_process_id_name(), 10000);
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#else
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//->
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managed_shared_memory shmem(create_only, "MySharedMemory", 10000);
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//<-
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#endif
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//->
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//Create the unique reference counted object in shared memory
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N::reference_counted_class *ref_counted =
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shmem.construct<N::reference_counted_class>
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("ref_counted")(shmem.get_segment_manager());
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//Create an array of ten intrusive pointer owners in shared memory
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intrusive_ptr_owner *intrusive_owner_array =
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shmem.construct<intrusive_ptr_owner>
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(anonymous_instance)[10](ref_counted);
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//Now test that reference count is ten
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if(ref_counted->use_count() != 10)
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return 1;
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//Now destroy the array of intrusive pointer owners
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//This should destroy every intrusive_ptr and because of
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//that reference_counted_class will be destroyed
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shmem.destroy_ptr(intrusive_owner_array);
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//Now the reference counted object should have been destroyed
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if(shmem.find<intrusive_ptr_owner>("ref_counted").first)
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return 1;
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//Success!
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return 0;
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}
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//]
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#include <boost/interprocess/detail/config_end.hpp>
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